The scale of landscape modification that occurred as a result of Aboriginal land care is a matter of much academic debate but there is increasing evidence suggesting that when Europeans arrived in New Holland they were greeted by a landscape that had been considerably modified from its natural state. However, it was the biotic landscape that had been changed: in contrast to the major urban cultures the English knew of elsewhere in Europe, South America, North America and Asia this was a nomadic culture without the civic adornment of carefully engineered stone monuments, stone buildings, roads or bridges. There were no transport systems or beasts of burden and no wheel: people moved about in the way that they had moved from Africa to Australia, by walking. The most complex transport system consisted of simple water craft, although the entire continent was connected by walking tracks. There were very few physical indications of a human presence that had begun well before the occupation of Europe by modern man and tens of thousands of years before the occupation of North America. Obvious indications of their presence were very few, some archaeological artefacts, stone tools (microliths), pockets of rock art, a few stone bases to temporary dwellings, and several minor rocky reconfigurations like the weirs used to trap fish. There was no use of metals, no written language, and minimal plant cultivation: it was a Stone Age culture that had not experienced an urban or agrarian revolution and Europeans were usually only aware of Aboriginal presence through their temporary camps and the shell middens that remained from millennia of feasting by lakes and the sea – but mostly through the smoke produced by their fires.
Evidence of how Aboriginal land management techniques changed over time, and the scale of their environmental impact, is gleaned mostly from archaeological investigation together with biological and ecological research. Some evidence has also been obtained from the numerous descriptions and observations that are recorded in the journals, reports and letters of the early coastal navigators, settlers, explorers, and botanists, along with artists’ illustrations of the land and its vegetation as depicted in the period of coastal navigation and early British settlement. There are still diverging views on Aboriginal environmental impact some maintaining that this was negligeable while others like Tim Flannery have argued that they hunted the megafauna to extinction.
With attention focused on plants at least five ways in which Aboriginals have modified Australia’s vegetation can be listed; and all are still understood:
- use of wild plants for food and material culture
- transport of plant propagules along Dreaming trails
- effects of hunting and foraging on trophic relationships in the food chain
- the use of fire
It was through the use of fire that First Australians left their most enduring impact on the landscape, but we can outline in more detail some particular ways in which vegetational and ecological change could have occurred by the use of plants for food and material culture, as listed by Philip Clarke in his Aboriginal People and their Plants:
- Removing the edible crowns of Cabbage Palm (Livistona spp.)
- Collecting plant fruits, notably that of the parasitic mistletoes and native apples Solanumspp.
- Digging out yams, native truffles, and a wide range of corms, bulbs and tubers, especially those of sedges and bulrushes. Digging and replanting of yams in particular could give the appearance of worked fields
- Building shelters, ochre quarries and fish traps
- Eating grubs, especially root grubs. Explorer Basedow noted the ravages of root grubs when gathering ceased
- Middens of ash, bone and shell are found at ancient coastal, river and creek camping sites, built up over many generations and sometimes the sites of fruit trees that have probably grown from the seed of ancient feasts
- Tracks to sources of food and water, to mountain passes and sacred landscape features were maintained by fire
We will probably never know the full impact of Aboriginal burning and firestick farming. On the one hand we have the view of people like historian Bill Gammage contending that fire had been pervasive across the continent for many thousands of years, used by Aboriginals as a highly sophisticated and finely honed system of land management. That “Most Australia was burnt about every 1-5 years depending on local conditions and purposes 
However, different factors are at play in different regions and as different fire regimes may be applied according to local conditions, so caution is needed in making generalisations about fire regimes of the past. Ecologically there seems a strong interdependence of fire, kangaroos, humans and grassland.
Many species are clearly adapted to fire and their numbers may have been increased by Aboriginal burning???. Possibly altered the balance of species through their hunting. Probably carried seeds, fruits and nuts around the country, digging and foraging being a form of cultivation. The winter clothing of Europeans was partly a product of pastures created by generations of Aboriginals.Blainey 83.
If Gammage is correct then the land was managed so well, and they trod on the land so lightly that western science has been unable to detect its presence, an incredibly subtle feat that nowadays grows annually in stature against the admired wonders of so-called civilisation from the pyramids, hanging gardens of Babylon, Roman roads and bridges to the modern megalopolis, space flights and nuclear fission.
Aboriginal influence on vegetation has been estimated through the presence of charcoal dated in sedimentary layers. The current superdominance of Eucalyptus in Australia may be a relatively recent phenomenon, the result of the extraordinary adaptation of the genus to fire.This was no doubt combined with the impact of Aboriginal burning.
There is a complex relationship between fire, vegetation types, fauna (extinctions and the effect of introduced carnivores and herbivores). Some animals probably multiplied through Aboriginal effect on predators or vegetation etc.
In recent times there has been a closer attention to climate modeling as a result of vegetation change as different vegetation types can influence evaporation and rainfall, alter surface reflectivity which, in turn, leads to changes in the weather and climate. Early studies are trying to assess the effect, on a global scale, of early agriculture involving land clearing and livestock, while in Australia there is the possible influence of Aboriginal burning. An “early anthropogenic hypothesis”, though slightly controversial, suggests that these practices had a definite influence on climate, agriculturalists producing an anomalous reversal in natural declines of atmospheric carbon dioxide 7,000 years ago and methane about 5,000 years ago.
Many of the food plants of the north seem to have remained the same as those of Indonesia, Malaysia and the Philippines rather than Australian natives, possibly hinting to times past
Hunting & megafauna
The extinction of the megafauna becomes significant because of the removal of major herbivores and predators from the food chain. The scale of this impact is uncertain but ecologists are clearly of the view that it might have been sufficient to have had an observable effect on the vegetation.
Perhaps the nearest to a consensus view is that Aboriginal burning produced vegetational change that severely altered the food supply and diet of these animals. Also, their size alone would have made them vulnerable to fire, being unable to sustain speed or find safe cover during the fire. Often slow creatures with large body mass this would make them susceptible to both fire and hunting. Some would have been relatively tame, making obvious game animals while the young, especially, would be prone to human predation which would have had an immediate impact on population numbers, especially in animals with a long gestation period.
At the time of European settlement dingoes were in all major habitats, those in the west were larger than those in the east and although the common colour was reddish Brown there were black ones and an alpine variant with thick white fur. Archaeological evidence shows that the dingo was present in several parts of Australia by 3,000 to 3,500 BP though they are not currently present in Tasmania or Papua-New Guinea. It probably took less than 500 years for them to occupy the entire continent although they only have one breeding cycle a year. Dogs similar to the dingo are found across SE Asia including the Papua-New Guinea highlands with the possibility of transference across Torres Strait by the islanders who shared technologies with the mainland Aborigines. There is also a close resemblance to pariah dogs and their ancestors in India. Early Timor trade (in a SE Asia trading network known to exist for about 8,000 years probably linked to a marine network in the Indian Ocean) represents another possible point of entry. Aboriginals used them as pets, food, warmth and for hunting.
When the dingo arrived on the Australian mainland there were two other sizeable carnivores, the Tasmanian Tiger and the Tasmanian Devil and that there is little doubt that the dingo drove the Tiger to extinction (the most recent thylacine remains date to 2,200 BP) although Aboriginals may have also been involved. As the dingo competed with Aborigines for food like wallabies and kangaroos it is possible that as the Aboriginal population was increasing there was aneed to hunt smaller game.
Dingoes have a varied diet preferring animals of 10-20 kg, often killing more than they need and hunting in packs. Their impact seems clear as a study published in 1980 indicated that on the east side of the dingo-proof fence running from SA through Qld red kangaroo numbers were 166 times greater and emu numbers 20 times greater than in the ?west.
In the 14th century across the world, apart from the few elite and privileged wealthy the standard of living for almost all amounted to subsistence based on agriculture. In Europe this situation would gradually change as material standards gradually rose into the Industrial Revolution. However, it would be the 19th century before the material conditions of Europeans could be considered greater than those of Aboriginal Australians. While the First Australian settlers at Botany Bay waited in desperation for food supplies arriving in European ships the native people enjoyed high quality meat and a diversity of greens, seed and fruit. The material possessions so important to the European were a burden to the nomadic lifestyle. Personal initiative and enterprise was not measured in wealth but in the economy of efficient simplicity.
Walkabout was the means by which Aboriginals gained food (water), water, energy, and materials (artefacts) while facilitating social connections and reinforcing the spiritual connection with the land. This was all at once a trading system, transport system, and a method of resource collection and distribution. Tools from the land combined with muscle-power were the instruments of production.
As an extremely simple economic system its throughput was well within the assimilative and regenerative capacity of its environment, with the possible exception of some impacts produced by fire and hunting and there was a fair and efficient allocation of the resources needed for day-to-day living.
Harvesting and cultivation
Though exposed to Pacific agriculture, mainland Aboriginals did not take up plant cultivation of plants in plantations or ‘fields’, the reasons for this being unclear. Perhaps it was simply perceived as unnecessary encumbrance.
Plant distributions may have been altered locally as food has been carried from collecting sites to camp sites (fruit trees growing on and around middens) but long-distance transport is most likely for plants with spiritual or ornamental value as bulk food does not appear to have been part of trade, people going to the sites of plenty rather than carrying excess across land. Even so seed may have been traded across the continent, the most likely being wattle seed.
Management and occupation of defined and protected territories by people of particular language groups (nations) was clearly a form of land ownership. In another sense though the land owned its residents as Aboriginals carried a deep spiritual connection with the land through the Dreaming. Aboriginal law carried with it the obligation of land management: people ‘belonged’ to the land which was inherited by its occupants: This contrasted with the European ideas of strict physical land enclosure using walls and fences, combined with a process of buying, selling, and leasing.
Researchers have now learned to be cautious in making generalizations about Aboriginal culture. Across the continent there were different people with language groups operating under different cultural systems: there were widely divergent environmental factors and climates at play as customs, climate and plants could all differ widely from one area to th next.
The Dreaming, as law, incorporated empirical wisdom by placing restrictions on the use of resources by means of the taboo although sometimes the environmental logic was not apparent, as when for a long period no fish were eaten in Tasmania.
The estimate of Aboriginal population in 1788 often quoted to this day is that of social anthropologist Radcliffe-Brown who in the Australian Yearbook of 1930 estimated 300,000 while archaeologist John Mulvaney in 1999 has placed an upper limit of about 750,000. Certainly, as now, favourable environments like lakes, rivers, estuaries and the coast supported more concentrated populations, notably parts of the Arnhem Land coast in the north, the east coast, south-west and probably highest in the Murray-Darling basin. Whether some sort of population equilibrium had been reached between population and environment in each language group area is a matter of conjecture?
Several factors acted as a curb on population numbers. For nomads only one breast-fed child-in-arms was manageable, especially as women were also expected to carry camping tools, food and possibly a firestick. Infanticide was widely practiced across the continent and it included: deformed children; twins; babies born in quick succession; illegitimate children; those born when the mother died in childbirth; there were also induced abortions. Cannibalism, although practiced, probably had a minimal effect and was rarely a motive for killing:  battles and killings by spearing or clubbing were quite frequent. It seems likely that population increase and recovery would generally have been extremely slow.
William Buckley (1780 – 1856), a military man said to stand 6’6” (198cm) tall and who lived with the Wathaurung people on the Bellarine Peninsula for 32 years experienced frequent killing and bloodshed. Evidence from many sourcs indicates Aboriginal life as violent and fearful based on retribution, raids and internal warfare. Perhaps Edward Stone Parker (1802-1865), who was Assistant Protector of Aborigines living at Mount Franklin District between Ballarat and Bendigo in Victoria, expressed the situation well as ‘On the whole their way of life was a satisfactory one, and could have been almost idyllic – but for their frequent fighting and persistent fear of revenge‘.
In SW Victoria channels were built between swamps as an aid to eel farming. At Lake Condah there were what are probably the greatest structural modifications known, including stone races, canals, traps and stone walls, the canals up to 1 m deep and 300 m long in an elaborate eel-farming complex where there were also houses with stone foundations with low stone walls suitable for a single family. Other tidal fish traps were built on the Barwon River and have also been found on the coast. One paddock contained 146 of these structures together suggesting a village population of about 700 people. The discovery, made in 1981, is probably the single best example of sedentism in Australia.
Mostly late Holocene shell middens occur along most of the Australian coastline, their alkaline soils made of shells sometimes supporting a characteristic flora along with the fruits of trees of generations of plants resulting from spit pips.
Firing could result in erosion and the washing of silt from higher to lower ground.
Population density increases in the last 5,000 years, the introduction of the dingo, with alteration of trophic relations and vegetational change through anthropogenic burning. Some, but still relatively, little physical impact.
Aboriginal land management can cause large-scale and long-term modification of the environment including animal and plant extinctions – though at nothing like the rate of European land management practices. Aboriginal disturbance is likely to recover within a generation or two.
A balanced account of Aboriginal environmental change during c. 50,000 years of occupation cannot be considered without some mention of the subsequent European impacts over 250 years: conversion of land to agriculture with practices that alter the soil composition, chemistry and water regimes, grazing over about 60% of the land and the impact of hooved and other domesticated animals; forestry; urban settlements; creation of continent-wide connecting roads and railways, diversion and alteration of waterways by dams, weirs, artificial lakes and irrigation schemes; introduction of feral plants and animals, fox, cat, camel, brumby, water buffalo, pigs, birds, rats and mice, rabbits.
Difficult discussions concerning conservation, restoration, pristine nature and what all these words mean and entail can be complicated and unproductive. The idea of sustainability though equally dogged by imprecision nevertheless conveys the idea of preserving the natural environment as best we can for the benefit of future generations. How that can be done is discussed elsewhere on this site.
Finally it is interesting, though perhaps unproductive in many ways, to speculate on the possible path of Aboriginal culture had Europeans not occupied the continent. Perhaps Australia was best suited to a hunter-gatherer lifestyle rather than agriculture, for example, which is more likely were there is regular and reliable rainfall and domesticated animals. (see social evolution)
Tasmanians were the most southerly population on earth.
Coastal archaeological sites are now under water.
By 20,000 BP there are sites in mountains, deserts and across the continent[K p.23]
The environmental impact of small groups of nomadic people would have been negligible, possibly some alteration to animal populations with its subsequent trophic cascade as a consequence of hunting, plant consumption and redistribution (see Pre-settlement plant introduction) and possibly some influence through fire: impact was probably related to individual consumption and therefore population number. Even so it is tempting to speculate on why there was such expansive migration – was this a consequence of using up food supplies and therefore a constant search for greater abundance and variety of food? Was it to avoid possible violent contact with other tribes? Curiosity and a sense of adventure? We do not know.
The nomadic lifestyle meant that Aboriginals never formed large settled integrated communities where the scale of numbers could be exploited to produce monumental architecture, ocean-going ships, elaborate ceramics, industry, manufacturing, transport systems and infrastructure.
Burning would have consumed vast amounts of energy but this was compensated by regeneration although the effects of human burning are complex in relation to trophic cascades, vegetation structure, extinctions and general ecology.
Estimates of global prehistoric human population numbers is that at the end of the last Ice Age 12-13,000 years ago suggest 4 – 6 million people (about the number in present-day Melbourne) with an explosion in numbers during the Neolithic Agricultural Revolution to reach about 60-70 million by about 6,000 BP. However, some studies indicate an earlier rise before the Neolithic around 25,000 years ago noting that even during the glacial period conditions through the tropics would have been mild and fertile.
Yet other genetic data suggests that a period of population growth may have occurred in the Paleolithic perhaps 60,000-80,000 years ago. Workers used a large data set from 20 different genomic regions and mitochondrial DNA of individuals from 66 African and Eurasian populations comparing their results with archaeological findings. The reasons for this early population growth are unsure, possibly linked to the emergence of more advanced hunting technologies or the influence of climate change. Those populations in the Near East that later adopted a sedentary farming lifestyle during the Neolithic had undergone the greatest Paleolithic expansions while the Eurasian nomadic herders experienced only moderate Paleolithic growth and no expansion was detected in the African nomadic hunter-gatherers. Population growth may thus have contributed to the adoption of agriculture.